Dust is often referred to as the computer killer. Dust is probably responsible for more computer and component failures than anything else. If you were to check your computer right now and removed the enclosure you will probably find a dust ball has built up inside the machine.
The problem with dust is that it can be comprised of literally any substance from skin cells to metals. It also has multiple effects on a computer system. Dust clogs filters and vents; this in turn causes a machine to over heat. Dust can also clog up moving parts such as hard drives and if it constitutes conductive materials it can also short circuit electrical boards.
In areas such as offices and homes, dust build up is not normally that severe. Regular cleaning of the inside of the machine (done very carefully) can normally prevent any major malfunctions although if there is high levels of dust then extra precautions should be taken such as plastic dust covers.
However, in applications such as in industry, production and manufacturing, dust can be at very high levels with many processes in industrial areas responsible for its creation and in this day-and-age, computers are prevalent everywhere and are just a common a sight in industrial areas as they are in offices.
While dustproof computers are available they are highly expensive but fortunately dustproof computing doesn’t have to cost the Earth. Dustproof industrial computer enclosures are a fraction of the price of industrial computers but offer the same if not better protection.